The present invention generally relates to fastening systems, and, more particularly, to a pre-assembled fastening system having a fastener secured in a fastener retainer.
The simple act of attaching one work piece to another using a threaded fastener in an assembly process, while simple to perform, can have a significant impact on overall assembly process efficiency. In the simple form of such an assembly operation, a bolt or the like is inserted through a hole in a first work piece, and is engaged in threads in a hole of a second work piece. When performed repetitively in an assembly process, seemingly small improvements in each such operation can have a significant overall effect.
It is known to provide fasteners in a grommet-like device that can be inserted and held in the hole of the first work piece. In this way, the first work piece with fastener can be pre-assembled, and when joined with the second work piece during the assembly process, the fastener is already in place for attaching the first and second work pieces together. Holding fasteners in fastener retainers held in one work piece also has advantages in assemblies that are disassembled occasionally or routinely. Fasteners are less likely to become lost, and re-assembly is simplified if the fasteners are held in position for reattachment.
Fasteners with fastener retainers, often referred to as captive fasteners, have taken on different forms, with differing results. U.S. Pat. No. 5,395,194 entitled xe2x80x9cCONVOLUTED BOLT RETAINERxe2x80x9d, for example, discloses a polymer retainer having a thin wall body member comprising an arrangement of alternating ribs and ears about a central opening. The polymeric retainer is pre-assembled into a shaped bore in a structural member, and is retained therein by elastic deformation of the retainer walls. The elastic body member retains a bolt shaft disposed in the opening thereof, prior to mounting of the structural member on a mounting surface.
A disadvantage of this design, however, is that a special stepped bore is required in the structural member. As such, the retainer cannot be used with structures having conventional holes. An additional disadvantages is that fastener systems constructed in accordance with the design are not adequately retained in the structure, and can become dislodged during shipment.
Other captive fastening systems have fastener retention members that engage the threads of the fastener, such that the fastener must be more or less threaded into or out of the fastener retention member, to adjust the axial position of the fastener relative to the fastener retention member. The time required to secure the fastener in the retention member, or to adjust the relative position of the fastener in the retention member when final assembly is performed is lengthened in such systems.
Captive fastener systems having a cylindrical body received in a hole of one of the work pieces and an end flange to seat against a surface of the work piece also are known. A problem can occur if the flange scratches or gauges the surface of the work piece as the fastener is tightened, particularly if the surface of the work piece has a protective coating to inhibit corrosion of the work piece.
What is needed in the art is a fastener retention member of a captive fastener system that is retained securely in a hole of a work piece, without special shaping of the hole. It is further desirable that the fastener retention member grasp the fastener securely, at any position along the length of the fastener, whether at a threaded portion or at a smooth portion of the fastener shank, while still allowing axial adjustment of the fastener in the fastener retention member. Once seated in the hole, the fastener retention member should allow insertion or withdrawal of the fastener relative to the fastener retention member, without dislodging the fastener retention member. Further, it is desirable that the fastener retention members allow slight angular adjustment of the fastener within the hole in the work piece such that the captive fastener system compensates for slight misalignment between the first and second work pieces. Still further, it is desirable that the fastener retention member not spin relative to the work piece, and that scratching or gouging by the fastener retainer be minimized or eliminated.
The present invention provides a captive fastening system in which a shaped flange on a fastener retention member is provided to seat against a surface of a work piece without gouging or scratching the work piece. A fastener is held in the fastener retention member by an inwardly directed dimple that frictionally engages the outer surface of the fastener.
In one form thereof, the invention provides a captive fastener system with a fastener including a head and a shank, at least a portion of the shank having threads. A fastener retention member includes a cylindrical body having first and second ends and an axial opening between the first and second ends. A flange at one end of the cylindrical body extends radially outward from the axial opening. At least one work piece engagement member is adapted and arranged to engage a bore in a work piece. A single inwardly extending dimple in the cylindrical body frictionally engages the fastener shank. The dimple is of substantially hemispherical shape.
In another form thereof, the invention provides a fastener retention member with a cylindrical body having a first end and a second end, and an axial opening therethrough between the first end and the second end. The body includes a fastener retention member therein. A flange extends radially outwardly from the body, at one end of the body. The flange includes a plurality of flange segments each having flange segment ends. Adjacent segments are spaced from each other. The flange segment ends are angled in a direction away from the other of the ends of the body.
In still another form thereof, the invention provides a fastener retention member with a substantially cylindrical body having a first end and a second end, and an axial opening between the first end and the second end. The body is configured for holding a fastener therein. A flange extends outwardly of the body at one end thereof. The flange includes a plurality of flange segments each having flange segment ends. Adjacent segments are spaced from each other at the segment ends thereof. Each flange segment has a central region between the segment ends thereof, the central region being of arched configuration.
An advantage of the present invention is providing a captive fastener retention member that does not mar, scratch or gouge the surface of a work piece in which it is installed.
Another advantage of the present invention is providing a captive fastener system that adequately holds the fastener, but reduces the tendency for the retention member to rotate in the work piece.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features.